package cn.itcast.search.Service.impl;

import cn.itcast.feign.client.ItemClient;
import cn.itcast.hmall.dto.common.PageDTO;
import cn.itcast.hmall.dto.common.ResultDTO;
import cn.itcast.hmall.dto.item.SearchItemDTO;
import cn.itcast.hmall.dto.search.SearchReqDTO;
import cn.itcast.hmall.pojo.item.Item;
import cn.itcast.hmall.pojo.item.ItemDoc;
import cn.itcast.search.Service.SearchService;
import com.alibaba.fastjson.JSON;
import org.elasticsearch.action.bulk.BulkRequest;
import org.elasticsearch.action.delete.DeleteRequest;
import org.elasticsearch.action.index.IndexRequest;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.xcontent.XContentType;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.functionscore.FunctionScoreQueryBuilder;
import org.elasticsearch.index.query.functionscore.ScoreFunctionBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.aggregations.AggregationBuilders;
import org.elasticsearch.search.aggregations.Aggregations;
import org.elasticsearch.search.aggregations.bucket.terms.Terms;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightField;
import org.elasticsearch.search.sort.SortOrder;
import org.elasticsearch.search.suggest.Suggest;
import org.elasticsearch.search.suggest.SuggestBuilder;
import org.elasticsearch.search.suggest.SuggestBuilders;
import org.elasticsearch.search.suggest.completion.CompletionSuggestion;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.CollectionUtils;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


@Service
public class searchImpl implements SearchService {

    @Autowired
    private RestHighLevelClient client;

    @Autowired
    private ItemClient itemClient;

    /**
     * 全量数据导入接口
     * @return
     */
    @Override
    public ResultDTO importItemData() {
        SearchItemDTO searchItemDTO = new SearchItemDTO();
        Integer page = 1, size = 500;
        searchItemDTO.setSize(size);
        searchItemDTO.setPage(page++);

        PageDTO<Item> itemPageDTO = itemClient.PaginatedQueries(searchItemDTO);

        Integer total = itemPageDTO.getTotal().intValue();

        saveListToEs(itemPageDTO.getList());

        for (   ; page * size < total + size; page++) {
            searchItemDTO.setPage(page);
            List<Item> list = itemClient.PaginatedQueries(searchItemDTO).getList();
            saveListToEs(list);
        }
        return ResultDTO.ok();
    }
    /**
     * 搜索栏自动补全接口
     * @param key
     * @return  List<String>
     */
    @Override
    public List<String> getSuggestion(String key) {
        try {
            // 1.准备Request
            SearchRequest request = new SearchRequest("item");
            // 2.准备DSL
            request.source().suggest(new SuggestBuilder().addSuggestion(
                    "suggestions",
                    SuggestBuilders.completionSuggestion("suggestion")
                            .prefix(key)
                            .skipDuplicates(true)
                            .size(10)
            ));
            // 3.发起请求
            SearchResponse response = client.search(request, RequestOptions.DEFAULT);
            // 4.解析结果
            Suggest suggest = response.getSuggest();
            // 4.1.根据补全查询名称，获取补全结果
            CompletionSuggestion suggestions = suggest.getSuggestion("suggestions");
            // 4.2.获取options
            List<CompletionSuggestion.Entry.Option> options = suggestions.getOptions();
            // 4.3.遍历
            List<String> list = new ArrayList<>(options.size());
            for (CompletionSuggestion.Entry.Option option : options) {
                String text = option.getText().toString();
                list.add(text);
            }
            return list;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public PageDTO<ItemDoc> search(SearchReqDTO searchReqDTO) {
        try {
            // 1.准备Request
            SearchRequest request = new SearchRequest("item");
            // 2.准备DSL
            // 2.1.query
            buildBasicQuery(searchReqDTO, request);
            // 2.2.分页
            int page = searchReqDTO.getPage();
            int size = searchReqDTO.getSize();
            request.source().from((page - 1) * size).size(size);

            // 2.2.高亮
            request.source().highlighter(new HighlightBuilder().field("name").requireFieldMatch(false));


            // 排序方式
            String sortBy = searchReqDTO.getSortBy();
            if (sortBy != null && !sortBy.equals("")) {
                if (sortBy.equals("score")) {
                    request.source().sort("score", SortOrder.DESC);
                } else if (sortBy.equals("price")) {
                    request.source().sort("price", SortOrder.ASC);
                }
            }

            // 3.发送请求
            SearchResponse response = client.search(request, RequestOptions.DEFAULT);
            // 4.解析响应
            return handleResponse(response);

        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public void up(Long id) {
        try {
            Item itemByID = itemClient.ByIdQuery(id);
            ItemDoc itemDoc = new ItemDoc(itemByID);

            IndexRequest request = new IndexRequest("item").id(id.toString());
            request.source(JSON.toJSONString(itemDoc),XContentType.JSON);
            client.index(request, RequestOptions.DEFAULT);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    @Override
    public void down(Long id) {
        try {
            DeleteRequest request = new DeleteRequest("item", id.toString());
            client.delete(request, RequestOptions.DEFAULT);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }


    private void buildBasicQuery(SearchReqDTO searchReqDTO, SearchRequest request) {
        // 1.构建BooleanQuery
        BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
        // 2.关键字搜索
        String key = searchReqDTO.getKey();
        if (key == null || "".equals(key)) {
            boolQuery.must(QueryBuilders.matchAllQuery());
        } else {
            boolQuery.must(QueryBuilders.matchQuery("all", key));
        }
        // 4.品牌条件
        if (searchReqDTO.getBrand() != null && !searchReqDTO.getBrand().equals("")) {
            boolQuery.filter(QueryBuilders.termQuery("brand", searchReqDTO.getBrand()));
        }
        // 5.分类参数
        if (searchReqDTO.getCategory() != null && !searchReqDTO.getCategory().equals("")) {
            boolQuery.filter(QueryBuilders.termQuery("category", searchReqDTO.getCategory()));
        }
        // 6.价格
        if (searchReqDTO.getMinPrice() != null && searchReqDTO.getMaxPrice() != null) {
            boolQuery.filter(QueryBuilders
                    .rangeQuery("price")
                    .gte(searchReqDTO.getMinPrice()*100)
                    .lte(searchReqDTO.getMaxPrice()*100)
            );
        }

        // 2.算分控制
        FunctionScoreQueryBuilder functionScoreQuery =
                QueryBuilders.functionScoreQuery(
                        // 原始查询，相关性算分的查询
                        boolQuery,
                        // function score的数组
                        new FunctionScoreQueryBuilder.FilterFunctionBuilder[]{
                                // 其中的一个function score 元素
                                new FunctionScoreQueryBuilder.FilterFunctionBuilder(
                                        // 过滤条件
                                        QueryBuilders.termQuery("isAD", true),
                                        // 算分函数
                                        ScoreFunctionBuilders.weightFactorFunction(10)
                                )
                        });
        // 7.放入source
        request.source().query(functionScoreQuery);


    }

    // 结果解析
    private PageDTO<ItemDoc> handleResponse(SearchResponse response) {
        // 4.解析响应
        SearchHits searchHits = response.getHits();
        // 4.1.获取总条数
        long total = searchHits.getTotalHits().value;
        // 4.2.文档数组
        SearchHit[] hits = searchHits.getHits();
        // 4.3.遍历
        List<ItemDoc> hotels = new ArrayList<ItemDoc>();
        for (SearchHit hit : hits) {
            // 获取文档source
            String json = hit.getSourceAsString();
            // 反序列化
            ItemDoc itemDoc = JSON.parseObject(json, ItemDoc.class);
            // 获取高亮结果
            Map<String, HighlightField> highlightFields = hit.getHighlightFields();
            if (!CollectionUtils.isEmpty(highlightFields)) {
                // 根据字段名获取高亮结果
                HighlightField highlightField = highlightFields.get("name");
                if (highlightField != null) {
                    // 获取高亮值
                    String name = highlightField.getFragments()[0].string();
                    // 覆盖非高亮结果
                    itemDoc.setName(name);
                }
            }

            // 放入集合
            hotels.add(itemDoc);
        }
        // 4.4.封装返回
        return new PageDTO<ItemDoc>(total, hotels);
    }

    //用户搜索条件改变时，搜索结果会跟着变化
    @Override
    public Map<String, List<String>> getFilters(SearchReqDTO searchReqDTO) {
        try {
            // 1.准备Request
            SearchRequest request = new SearchRequest("item");
            // 2.准备DSL
            // 2.1.query
            buildBasicQuery(searchReqDTO, request);
            // 2.2.设置size
            request.source().size(searchReqDTO.getSize());
            // 2.3.聚合
            buildAggregation(request);
            // 3.发出请求
            SearchResponse response = client.search(request, RequestOptions.DEFAULT);
            // 4.解析结果
            Map<String, List<String>> result = new HashMap<>();
            Aggregations aggregations = response.getAggregations();
            // 4.2.根据品牌名称，获取品牌结果
            List<String> brandList = getAggByName(aggregations, "brandAgg");
            result.put("brand", brandList);
            List<String> categoryList = getAggByName(aggregations, "categoryAgg");
            result.put("category", categoryList);

            return result;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }


    private void buildAggregation(SearchRequest request) {
        request.source().aggregation(AggregationBuilders
                .terms("brandAgg")
                .field("brand")
                .size(100)
        );
        request.source().aggregation(AggregationBuilders
                .terms("categoryAgg")
                .field("category")
                .size(100)
        );
    }

    private List<String> getAggByName(Aggregations aggregations, String aggName) {
        // 4.1.根据聚合名称获取聚合结果
        Terms brandTerms = aggregations.get(aggName);
        // 4.2.获取buckets
        List<? extends Terms.Bucket> buckets = brandTerms.getBuckets();
        // 4.3.遍历
        List<String> brandList = new ArrayList<>();
        for (Terms.Bucket bucket : buckets) {
            // 4.4.获取key
            String key = bucket.getKeyAsString();
            brandList.add(key);
        }
        return brandList;
    }


    private void saveListToEs(List<Item> list) {
        BulkRequest bulkRequest = new BulkRequest();
        for (Item item : list) {
            ItemDoc itemDoc = new ItemDoc(item);
            bulkRequest.add(
                    new IndexRequest("item")
                            .id(itemDoc.getId().toString())
                            .source(JSON.toJSONString(itemDoc), XContentType.JSON)
            );
        }
        try {
            client.bulk(bulkRequest, RequestOptions.DEFAULT);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }


}
